Compressing one image is easy. Compressing a whole set well means making consistent decisions: the same maximum dimensions, a sensible output format, predictable quality, and file names you can trace back to the originals.

A batch workflow is useful for product catalogues, blog posts, portfolios, property listings, and any page that loads several photos at once. The aim is not simply to produce the smallest possible files. It is to remove waste while keeping every image fit for its job.

Decide the output rules before adding files

Write down three choices first:

  1. Maximum dimensions. Match the largest size the site actually displays. A thumbnail and a full-width hero should not use the same dimensions.
  2. Format. WebP is a practical default for web photographs and mixed graphics. Keep PNG when lossless detail or transparency is essential; consider SVG for simple logos and icons.
  3. Quality. Start around the middle-high range, then inspect a detailed sample. Hair, foliage, gradients, and small interface text reveal compression damage quickly.

Using one rule for a visually similar group creates more predictable results than tuning every file at random.

A repeatable batch workflow

  1. Separate images by purpose: thumbnails, content images, hero images, and transparent graphics.
  2. Open Image Compression and add one group at a time.
  3. Apply the target format, quality, and dimensions to the group.
  4. Preview the most demanding image, not only the easiest one.
  5. Process the batch and compare the output sizes.
  6. Open a few results at their real display size before replacing the originals.

Always keep the source files. Optimized web images are delivery copies, not new masters. If the design changes later, you will want to create a fresh export rather than enlarge an already compressed image.

Do not mix unlike images blindly

A single setting rarely suits everything:

  • Photographs usually tolerate lossy compression well.
  • Screenshots with small text need higher quality and may need their original dimensions.
  • Transparent graphics require an output format that preserves transparency.
  • Logos with flat shapes may be better converted to vector instead of compressed as pixels.

Split these into separate batches. It takes one extra minute and prevents a setting chosen for photos from making text or sharp edges look poor.

If you are unsure about the output format, compare the tradeoffs in WebP vs AVIF vs JPEG. For logos and line art, see the bitmap-to-vector guide.

Check visual quality where people will see it

Zooming to 400% is useful for finding artifacts, but it is not the final test. View the optimized image at its actual size inside the page. A tiny difference under extreme zoom may be invisible to visitors, while a slightly soft product label at normal size may be unacceptable.

Pay special attention to:

  • fine text and price labels;
  • gradients and skies that can show banding;
  • faces, hair, and fabric texture;
  • hard color boundaries around graphics;
  • transparent edges on dark and light backgrounds.

Name and organize the results

Keep a predictable naming pattern, such as product-name-800.webp, and place optimized files in a separate folder until they have been reviewed. Dimensions in the name make later maintenance easier, especially when the same source image has thumbnail and large versions.

Because browser-local compression does not upload the source images, it is also a sensible workflow for unreleased products, client work, and private screenshots.

Ready to optimize a set? Drop a group into Image Compression, apply one consistent recipe, and review the output before publishing.